Hazmat crews spent most of the afternoon at Yale-New Haven Hospital after a powdery substance was discovered in a public waiting area.
New Haven and Guilford hazmat and fire crews as well as the FBI spent three hours on the scene. They wrapped up just after 4 p.m.
After testing, they determined that the white powder found inside the hospital was not a threat.
The security team was called in at 1 p.m. when someone spotted that powder in a baggy inside the atrium near the emergency room.
Decontamination equipment was laid out in the ambulance entrance, but was never used.
Because evacuations never took place, hospital officials said the impact was minor.
The security guard who responded and came in close contact with the substance was put under quarantine, but did not show any negative effects.